JP4539397B2 - Method for producing ceramic dental prosthesis - Google Patents

Description

  The present invention relates to a method for producing a ceramic dental prosthesis.

  In recent years, CAD (Computer Aided Design) / CAM (Computer Aided Manufacturing) has been applied in dentistry, and a method of manufacturing a ceramic dental prosthesis using CAD / CAM is known. In such a method, when cutting a densely sintered ceramic material, a great amount of time is required for the cutting because of the hardness of the densely sintered ceramic material, and the wear of the processing tool is remarkably high. There was a problem of becoming.

In order to solve such problems, for example, in Patent Document 1 and Patent Document 2, a dental prosthesis is manufactured by cutting a material that has been pre-sintered to a certain degree of hardness and then performing dense sintering. How to do is described.
Japanese Patent No. 3492419 Special table 2003-506191 gazette

  However, in the production methods described in Patent Document 1 and Patent Document 2 described above, sufficient study has been made in the case of using ceramic powder mainly composed of tetragonal zirconia oxide particles containing cerium oxide and aluminum oxide particles as raw materials. As for a dental prosthesis manufactured from such a raw material, a high-strength dental prosthesis that can be used is obtained, and a manufacturing method that can be manufactured in a short time is not known. Moreover, in the said patent document 1 and patent document 2, examination regarding the process temperature (henceforth a presintering temperature) in the presintering process and the intensity | strength of the manufactured dental prosthesis is not fully made | formed.

  The present invention has been made to solve the above-mentioned problems, and uses high-strength dental materials that can withstand use by using ceramic powders composed mainly of tetragonal zirconia oxide particles containing cerium oxide and aluminum oxide particles as raw materials. An object of the present invention is to provide a method for producing a ceramic dental prosthesis capable of producing a prosthesis and capable of producing the dental prosthesis in a short time.

In order to achieve the above object, the invention according to claim 1 is characterized in that zirconium oxide 65.9 to 69.9 layer
% By weight, cerium oxide 10.1-11.1% by weight, aluminum oxide 19.5-23.5 weight
% By weight, titanium oxide 0.01-0.03%, and magnesium oxide 0.04-0.08 weight
% Of a ceramic composite prosthesis comprising, as a raw material composition, a cold isotropic addition of a raw material composition mainly composed of tetragonal zirconium oxide particles and aluminum oxide particles. A green compact forming step for obtaining a green compact by molding by pressing (CIP: Cold Isostatic Pressing), and a green compact obtained in the green compact forming step is shaped into a predetermined shape to obtain a shaped body. A pre-sintering step in which a pre-sintered body is obtained by pre-sintering the shaping body obtained in the shaping step and the shaping body obtained in the shaping step at a temperature lower than the temperature at which the shaping body is densely sintered; A cutting process obtained by cutting the pre-sintered body obtained in the pre-sintering process into substantially the same shape as a dental prosthesis as a finished product, and a cutting obtained by the cutting process The machined body is densely sintered. Includes a dense sintered to obtain a dental prosthesis densely sintered at a temperature, a treatment temperature in the preliminary sintering process, characterized in that at 1100 ° C. or higher 1300 ° C. or less.

The invention of claim 2 is the method for producing a ceramic dental prosthesis according to claim 1 , wherein the bending strength of the pre-sintered body obtained in the pre-sintering step is in the range of 35 to 500 MPa. Features.

  According to the present invention, a pre-sintered body obtained by pre-sintering using a raw material blend mainly composed of tetragonal zirconium oxide particles containing 8 to 12 mol% of cerium oxide as a stabilizer and aluminum oxide particles. Since the dental prosthesis is manufactured by cutting and thereafter densely sintering, it becomes possible to manufacture the ceramic dental prosthesis in a short time.

  Moreover, by setting the pre-sintering temperature in the range of 1100 ° C. or more and less than 1450, it is possible to prevent the strength of the manufactured dental prosthesis from being lowered and shorten the time required for cutting.

  In addition, by setting the bending strength of the pre-sintered body obtained in the pre-sintering step to a range of 35 to 500 MPa, the strength of the manufactured dental prosthesis is prevented from being reduced and the time required for cutting is shortened. can do.

  Hereinafter, the manufacturing method of the ceramic dental prosthesis which concerns on one Embodiment of this invention is demonstrated with reference to FIG.1 and FIG.2. This production method is a method for producing a dental prosthesis comprising a ceramic composite mainly composed of tetragonal zirconium oxide particles containing 8 to 12 mol% of cerium oxide as a stabilizer and aluminum oxide particles, and has the following pressure. It includes a powder molding process, a shaping process, a pre-sintering process, a cutting process, and a dense sintering process. In FIGS. 1 and 2, an explanatory diagram of each process is shown on the left side, and a molded body produced from each process is shown on the right side.

  As shown in FIG. 1 (a), in the green compact forming process, a cold isostatic pressing (CIP) apparatus 10 is used, and tetragonal crystal containing 8 to 12 mol% of cerium oxide as a stabilizer. A raw material mixture mainly composed of zirconium oxide particles and aluminum oxide particles is sealed in a molding mold 10a together with a binder, and pressure is applied through an upper punch 10b and a lower punch 10c to obtain a green compact 1. In addition, the adjustment method of a raw material mixture is not specifically limited, For example, it adjusts by the method described in patent 2945935.

  As shown in FIG. 1B, in the shaping process, the green compact 1 obtained in the green compact forming process is cut using a lathe device 20 or the like, and the cutting process is performed in a cutting process described later. The green compact 1 is shaped into a columnar shape (predetermined shape) or the like so as to make it easy to obtain a shaped body 2.

  Then, as shown in FIG. 2 (a), in the preliminary sintering step, the shaped body 2 obtained in the shaping step is placed in the sintering furnace 30, and the shaped body 2 is removed by the heat source 30a. The binder is removed by heating and presintered at a temperature lower than the temperature at which the shaped body 2 is densely sintered to obtain the presintered body 3. The pre-sintering temperature is not particularly limited as long as it is lower than the temperature at which the shaped body 2 is densely sintered, but is preferably in the range of 1100 ° C. or higher and lower than 1450 ° C. If the temperature is lower than 1100 ° C., the strength of the dental prosthesis manufactured as described later is lowered, and if it is 1450 ° C. or higher, the orthopedic processed body 2 is densely sintered, which may require an enormous amount of time for cutting. is there. The bending strength of the pre-sintered body 3 obtained in the pre-sintering step is preferably in the range of 35 to 500 MPa. This is because if the bending strength of the pre-sintered body 3 is smaller than 35 MPa, the strength of the manufactured dental prosthesis is lowered, and if it is larger than 500 MPa, a long time is required for cutting. In addition, the bending strength in this specification means the bending strength measured from the three-point bending test of JIS R1601.

  As shown in FIG. 2B, in the cutting process, the pre-sintered body 3 obtained in the pre-sintering process has substantially the same shape as a dental prosthesis that is a finished product using the CAD / CAM device 21 or the like. To obtain a cutting body 4. In the dense sintering step, which will be described later, when the cutting body 4 is densely sintered, the dimensions of the cutting body 4 may change due to the shrinkage of the cutting body 4. 4 is preferably processed.

  As shown in FIG. 2 (c), in the dense sintering step, the temperature at which the cutting body 4 obtained by the cutting step is placed in the sintering furnace 30 and the cutting body 4 is densely sintered. To obtain a dental prosthesis 5.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these Examples at all.

Example 1
According to the method described in Japanese Patent No. 2945935, zirconium oxide 65.9 to 69.9% by weight, cerium oxide 10.1 to 11.1% by weight, aluminum oxide 19.5 to 23.5% by weight, titanium oxide A raw material mixture containing 0.01 to 0.03% by weight and magnesium oxide 0.04 to 0.08% by weight was prepared, and the prepared raw material mixture was CIP-molded to prepare a green compact. A shaped body was obtained by shaping into a cylindrical shape. Then, the shaped body thus obtained is pre-sintered at 1200 ° C. to prepare a pre-sintered body, and this is cut using a DentaCAD systeme dmmx manufactured by Hint-ELs, Germany, as a cutting body 3 A crown was created. And this cutting processed object was densely sintered at 1450 degreeC, and the dental prosthesis was finally obtained.

(Example 2)
A dental prosthesis was obtained in the same manner as in Example 1 except that the presintering temperature was 1300 ° C.

(Comparative example)
Using the same raw material composition as in Example 1, the CIP-molded green compact is shaped into a cylindrical body to produce a shaped body, and this shaped body is densely sintered at 1450 ° C. Created the body. Further, this dense sintered body was cut using a DentaCAD systeme dmmx manufactured by Hint-ELs, Germany, and a triple crown was created to obtain a dental prosthesis.

Production conditions of Example 1, Example 2 and Comparative Example, bending strength of the pre-sintered body obtained by Example 1 and Example 2, and bending strength of the dense sintered body obtained by Comparative Example Table 1 shows. The bending strength was measured by preparing a 40 mm × 3 mm × 4 mm test piece and conducting a three-point bending test in accordance with JIS R1601, as in Examples 3 to 5 described later.

  FIG. 3 shows the time required for cutting in Examples 1 and 2 and the comparative example. In this figure, (a) shows Example 1, (b) shows Example 2, and (c) shows a comparative example. As shown in the figure, the time required for cutting of Example 1 that was pre-sintered at 1200 ° C. was 1/3 or less of the time required for cutting of the comparative example that was densely sintered at 1450 ° C. It can be seen that the cutting time can be significantly reduced.

(Example 3 to Example 5)
In Example 3, a dental prosthesis was obtained in the same manner as in Example 1 except that the pre-sintering temperature was set to 850 ° C., and the shape of the cut workpiece was set to 40 mm × 3 mm × 4 mm for a three-point bending strength test. In Example 4, a dental prosthesis was obtained in the same manner as in Example 3 except that the pre-sintering temperature was 1050 ° C. In Example 5, a dental prosthesis was obtained in the same manner as in Example 3 except that the pre-sintering temperature was 1100 ° C.

The manufacturing conditions of Examples 3 to 5 above, and the three-point bending strength of the pre-sintered body of Example 3 to Example 5 and the three-point bending strength of the dense sintered body performed according to JIS R1601. It shows in Table 2. FIG. 4 shows the relationship between the three-point bending strength and the pre-sintering temperature of the dense sintered bodies of Examples 3 to 5 together with the three-point bending strength of the dense sintered body of the comparative example. In the figure, (a) shows Example 3, (b) shows Example 4, (c) shows Example 5, and (d) shows a comparative example.

  As shown in FIG. 4, the three-point bending strength of the dense sintered body of Example 5 is abruptly increased compared to the three-point bending strength of the dense sintered bodies of Example 3 and Example 4. It can be seen that there is a large difference in strength at the presintering temperature of 1100 ° C. Further, the three-point bending strength of the comparative example obtained by cutting the dense sintered body is higher than the respective three-point bending strengths of Examples 3 to 5 obtained by cutting the pre-sintered body. I understand that

  Thus, the strength of the dental prosthesis obtained by densely sintering after cutting the pre-sintered body is higher than that of a dental prosthesis obtained by cutting the dense sintered body. Although lowering, by setting the pre-sintering temperature to a predetermined temperature or higher, that is, to 1100 ° C. or higher shown in the present embodiment, it is possible to suppress a decrease in strength of the finally produced dental prosthesis.

  In this way, the presintering temperature is set to 1100 ° C. or higher and lower than 1450 ° C. (the cutting body is densely sintered at a temperature of 1450 ° C. or higher), and the obtained presintered body is cut and then densely sintered. As a result, a dental prosthesis having high strength can be manufactured, and the cutting time can be shortened.

Next, the cause of the rapid bending strength fluctuation of the dental prosthesis with the pre-sintering temperature of 1050 to 1100 ° C. as a boundary will be discussed with reference to FIGS. FIG. 5A shows a dental prosthesis obtained in Example 3 processed into a disc shape (φ12 mm × t1.0 mm), and the surface thereof was observed with a scanning electron microscope (SEM). 5 (b) is an observation of a dense sintered body obtained by the same method as in the comparative example in the same disk shape. Table 3 shows the density of the dental prosthesis manufactured according to Example 3 and the comparative example.

  As shown in these SEM photographs and Table 3, in the sample obtained in Example 3, powder particles were observed despite the dense sintering after cutting, and the density was lower than that of the comparative example. It can be seen that the porosity is low. Therefore, a dental prosthesis obtained by cutting a pre-sintered body obtained by pre-sintering and then densely sintering it is a dental prosthesis obtained by cutting after a dense sintered body. Compared to the prosthesis, it is considered that the strength is lowered because the sintering during the dense sintering is not completely performed.

It is explanatory drawing of the manufacturing method of the ceramic dental prosthesis which concerns on one Embodiment of this invention, (a) is a compacting process, (b) is a figure which shows a shaping process, respectively. (A) is the preliminary | backup sintering process of the manufacturing method, (b) is a cutting process, (c) is a figure which shows a dense sintering process, respectively. The graph which shows the relationship between the pre-sintering temperature before cutting, and cutting time. The graph which shows the relationship between the sintering temperature before cutting, and the three-point bending strength of the manufactured ceramic dental prosthesis. (A) is a SEM photograph of the ceramic dental prosthesis obtained in Example 3, and (b) is a SEM photograph of the ceramic dental prosthesis obtained in the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compact 2 Shaped body 3 Pre-sintered body 4 Cutting body 5 Dental prosthesis

Claims (2)

Zirconium oxide 65.9 to 69.9% by weight, cerium oxide 10.1 to 11.1% by weight
19.5 to 23.5% by weight of aluminum oxide, 0.01 to 0.03% of titanium oxide, and
A method for producing a ceramic dental prosthesis comprising a ceramic composite containing 0.04 to 0.08% by weight of magnesium oxide as a raw material composition,
A green compact molding step of obtaining a green compact by molding the raw material blend mainly composed of tetragonal zirconium oxide particles and aluminum oxide particles by cold isostatic pressing (CIP);
A shaping process that obtains a shaped body by shaping the green compact obtained in the green compact forming step into a predetermined shape;
A pre-sintering step of pre-sintering the shaped body obtained in the shaping process step at a temperature lower than the temperature at which the shaped body is densely sintered;
A cutting process that obtains a cut body by cutting the pre-sintered body obtained in the pre-sintering process into substantially the same shape as a dental prosthesis that is a finished product;
A dense sintered step of obtaining a dental prosthesis by densely sintering the cut body obtained by the cutting step at a temperature at which the cut body is densely sintered,
The method for producing a ceramic dental prosthesis, wherein a treatment temperature in the preliminary sintering step is 1100 ° C or higher and 1300 ° C or lower. 2. The method for producing a ceramic dental prosthesis according to claim 1, wherein the pre-sintered body obtained in the pre-sintering step has a bending strength in a range of 35 to 500 MPa.